Design and arrangement of the coolant pump of internal combustion engines



A. SCHEITERLEIN ET'AL 2,820,441

2 DESIGN AND ARRANGEMENT OF THE COOLANT Y. PUMP OF INTERNAL COMBUSTIONENGINES Fil-ed May 27, 1955 2 Sheets-Sheet 1 n-21,1958 A.SCHEITERLEM-FAL 2,820,441

DESIGN "AND ARRANGEMENT OF THE COOLANT PUMP OF INTERNAL COMBUSTIONENGINES Filed May 27, 1955 2 Sheets-Sheet 2 F763 1 IE V I I e I v I] 518 5 United States Patent DESIGN AND ARRANGEMENT OF THE COOLANT PUMP OFINTERNAL COMBUSTION ENGINES Andreas Scheiterlein and Othmar Skatsche,Graz, Austria, assignors to Gustav Ospelt, Vaduz, LiechtensteinApplication May 27, 1955, Serial No. 511,727 Claims priority,application Austria June 12, 1954 4 Claims. (Cl. 12.3-41.46)

This invention relates to a two-stroke internal combustion engine withvertical cylinders arranged in a row, each cylinder having apiston-controlled exhaust port, and wet cylinder liner, the liner beingsurrounded by a coolant chamber and a separate coolant chambersurrounding the exhaust passages in the cylinder block. For this type ofengine it has been known to arrange the coolant pump on the front sideof the cylinder block and to feed the two aforementioned coolantchambers with coolant through separate hose lines. This affordsefficient cooling both for the cylinder liners and the exhaust ports inthe cylinder block by means of fresh, cooled-down coolant. Since theamount of heat to be extracted from the cylinder liners is considerablylarger than for the exhaust passages, the coolant chamber around thecylinder liners will have to receive a correspondingly larger supply ofcoolant than the coolant chamber around the exhaust passages. Usuallythe amount of coolant delivered by the coolant pump is predetermined bythe use of different passage sections for the hose lines and byproviding chokes of appropriate dimensions along the coolant flow.

The disadvantage of the above arrangements resides in the fact that theallocation of supply depends on factors which are liable to dilfer toofreely from the proposed values or are subject to alterations in thecourse of time. Consequently, the uniform cooling of all parts is notpositively assured.

According to the invention, these drawbacks are avoided by providing acentrifugal coolant pump with two delivery channels, each of which isassigned to one of the coolant chambers, one of said channels feedingthe coolant chamber around the cylinder liners being connected at oneend and the other at the other end of the pressure groove of the coolantpump. Thus the pressure head and the delivery of the pump are divided ata fixed predetermined ratio. The distance between the delivery channelleading to the exhaust ports and the other end of the pressure groovewill determine the portion of the overall pressure head which isallocated to this delivery channel. Besides, the allocation ofdeliveries is largely independent of the pipe section used.

According to a further feature of the invention the housing of thecoolant pump and the two delivery channels constitute a single casting,the delivery channels being connected to the coolant chambers throughthe surface of attachment of the coolant pump on the cylinder block.This eliminates the need for hose connections, simplifies installationand increases the safety of operation. In addition since the sections ofthe delivery channels are determined in advance, it is impossible forthe cooling conditions to be adversely affected by the use of hoseconnections of unsuitable section, as may happen during repairs forinstance.

According to further embodiments of the invention, provision has beenmade for the delivery channels and the coolant pump being drainedcompletely during the discharge of the coolant. This is achieved byappro- 2,820,441 Patented Jan. 21, 1958 The invention is illustrated byway of example in the accompanying drawings wherein:

Figure 1 shows a front view of the two-stroke engine with the coolantpump in section along the line I-I of Figure 2. Figure 2 shows thecoolant pump in section along the line II-II of Figure 1 and Figure 3 apartial vertical section through the axis of a cylinder.

The cylinder block of the two-stroke engine is designated by 1, thecylinder liner by 2, the cylinder head by 3, the piston by 4 and theconnecting rod by 5. The cylinder liner 2 is inserted in the cylinderblock 1 and both together constitute the coolant chamber 6, the lowerportion 6' of which is enlarged. It is clamped at the upper end andfixed together with the cylinder head 3 by means of cylinder head screws7. At other points the cylinder liner is slidable for axial expansionand sealed by means of rubber rings 8. The coolant is delivered into thecoolant chamber 6 by the coolant pump 9 through an aperture 10 and theconnecting passage 10 in the cylinder block and flows through saidchamber 6 and the chamber 6 while cooling the cylinder liner 2, and thenpasses through passage apertures 11 into the cavity of the cylinder head3. A nipple 12 is provided on the cylinder head for the discharge of thecoolant.

The exhaust ports 13 of the engine are controlled by a piston 4 and leadto discharge channels 14 of the cylinder block and from there into theexhaust manifold 15. The discharge channels 14 in the cylinder block aresurrounded by a separate coolant chamber 16, the upper portion of whichcommunicates with the coolant chamber 6 by means of apertures 17. Thecoolant is delivered into the coolant chamber 16 through a passageaperture 18 located at its lowest point 16'.

The coolant pump 9 consists of a rotor 19 driven in the usual manner(not shown in the drawings) from a V-belt pulley 20 via a shaft 34 bythe crankshaft. The pump intake is designated by 21 and the suctionchamber by 22. The pressure groove 23 surrounding the rotor 19communicates at one end with a short delivery channel 23' communicatingwith the passage aperture 10 in the cylinder block via the surface ofattachment 24 of the pump. A second pressure channel 25 is located nearother end of the pressure groove and connected to the latter and leadsalso through the surface of attachment 24 to the passage opening 18 ofthe cylinder block. The delivery channel 25 is slightly inclined fromthe outside toward the center of the pump. At its lowest point a smallconnecting duct 27 has been provided. These measures ensure the completedischarge of the coolant pump and the delivery channels during thedraining of the coolant. The bore 27' is required for manufacturingpurposes only and otherwise closed. The housing 28 of the coolant pumpincluding the delivery groove 23 and the delivery channels 23 and 25 areformed by a single casting. The pump is fixed with the interposition ofa plate 29 by means of screws inserted in the bores 30.

The scavenging air blower is designated by 31, the starter by 32 and thefront cover of the casing by 33.

I claim:

1. In a two-stroke internal combustion engine, the combinationcomprising a cylinder block having vertical cylinders arranged in a row,with reciprocating pistons, wet cylinder liners surrounded by a coolantchamber, pistoncontrolled exhaust ports, exhaust channels in thecylinder block surrounded by a separate coolant chamber, a coolant pumpof the centrifugal type arranged at the front end of the cylinder block,with a pressure groove and two delivery channels, each of which isassigned to one 'ofthe coolant chambers, one of said channels feed ingthe coolant chamber around the cylinder liners being connected at oneendof the pressure groove of the coolant pump, whereas the. other channelfeeding the coolant chamber surrounding the exhaust passages isconnected at the other end of said pressure groove.-

2. The combination according to claim 1. and wherein the housing of saidcoolant pump and its two delivery channels are formed by a singlecasting, said delivery channels communicating with said coolant chambersthrough the surface of attachment of' the coolant pump.

3. The combination according to claim 2 and-wherein ma e;

the delivery channel connected between the other end of the pressuregroove is either horizontal or slightly inclined toward the center ofthe pump, said channel being connected at the lowest point of saidpressure groove.

4. The combination according to claim 3 and wherein a small connectingduct is provided at the lowest pointof the delivery channel leading tothe suction chamber of the coolant pump.

References Cited in the file of this patent UNITED STATES PATENTS2,216,802 Baster Oct. 8, 1940

